陆态网基准站的坐标和速度

介绍“中国大陆构造环境监测网络”GNSS基准站观测数据的处理和分析.数据处理基于陆态网工程2010-07-01 -2012-03-16日的252个GNSS基准站观测数据,获得了基准站的坐标单日解时间序列,利用抗差最小二乘估计拟合出了这些站的速度场.     

斑岩型铜(钼)矿床和斑岩型钼(铜)矿床的形成机制探讨:流体演化及构造背景的影响

斑岩型铜(钼)矿床和斑岩型钼(铜)矿床是世界钼资源最主要的来源,提供的钼金属量相当。对比发现,两类矿床在流体来源演化以及铜和钼的相关性上较为相似,而在铜/钼比值、品位、矿物共生组合、蚀变类型等方面存在差异,特别是斑岩铜(钼)矿初始出溶流体中的Cl-/F-值、硫的总量、SO2/H2S以及H+/ K+比斑岩钼(铜)矿高。流体演化过程中有两方面因素可能影响最终沉淀的铜和钼比值：(1)铜和钼在流体中的性质差异,如铜以氯或硫络合物形式运移,沉淀受温度影响比较显著,钼以羟基或氯络合物形式存在,沉淀受压力控制比较明显;(2)流体自身氧逸度、pH、硫逸度的变化以及演化路径的改变。然而,和初始流体性质的差异相比,流体演化过程对最终形成矿床类型的影响是有限的,决定矿床形成斑岩铜(钼)矿化还是钼(铜)矿化的因素可能在流体出溶之前的岩浆起源演化阶段就存在。斑岩铜(钼)矿常分布在偏挤压的陆缘弧和大陆碰撞造山带环境,基底多为新生或加厚的陆壳,斑岩钼(铜)矿多出现在偏伸展的陆内裂谷、弧后及造山后伸展环境,基底可以为老陆壳或新生的陆壳;上述特征反映物源区或岩浆的起源和演化方式不同可能是制约形成斑岩铜(钼)矿还是钼(铜)矿的主要机制。     

Soil organic carbon pools in alpine to nival zones along an altitudinal gradient (4400–5300 m) on the Tibetan Plateau

To accurately estimate soil organic carbon (SOC) storage in upper alpine to nival zones on the Tibetan Plateau, we inventoried SOC pools in 0–0.3 m profiles along an altitudinal gradient (4400–5300 m asl). We also studied vegetation properties and decomposition activity along the gradient to provide insight into the mechanisms of SOC storage. The vegetation cover and belowground root biomass showed a gradual increased with altitude, reaching a peak in the upper alpine zone at 4800–4950 m before decreasing in the nival zone at 5200–5300 m.Decomposition activity was invariant along the altitudinal gradient except in the nival zone. SOC pools at lower sites were relatively small (2.6 kg C m⁻² at 4400 m), but increased sharply with altitude, reaching a peak in the upper alpine zone (4950 m; 13.7 kg C m⁻²) before decreasing (1.0 kg C m⁻² at 5300 m) with altitude in the nival zone. SOC pool varied greatly within individual alpine meadows by a factor of five or more, as did bulk density, partly due to the effect of grazing. Inventory data for both carbon density and bulk density along altitudinal gradients in alpine ecosystems are of crucial importance in estimating global tundra SOC storage.     

溃变理论在汕头暴雨天气预测中的应用

运用溃变理论的V-3θ图结构分析方法和溃变图分析了汕头的一场暴雨天气,说明怎样运用溃变理论对汕头暴雨天气进行预测分析。结果表明:V-3θ图对暴雨天气预测有着较好的指示特征,溃变图对天气形势的演变有较好的指示意义,溃变理论在暴雨天气预测中有参考价值。     

对我国地震预测研究的一些建议

由于美国帕克菲尔德地震的发生以及地震预测研究的进展,经过数年沉寂之后,国际上对地震预测的讨论又处于增温状态。     

网络存储技术在地震数据存储中的应用

随着地震观测和地震科学研究水平的提高,大量宝贵的地震科学数据不断产出.安全有效地存储这些海量地震数据,是目前迫切需要解决的问题.本文简要介绍了网络存储技术的发展和应用,并通过分析地震数据对存储系统的要求,探讨了网络存储技术在地震数据存储中的应用.     

Application of new concept waterproofing in Xiang’an undersea tunnel, China

As a kind of transportation mode for crossing channels,undersea tunnel has incomparable advantages for its directness,convenience,fastness,insusceptibility to weather conditions,and smaller influences on environments.In recent years,with the development of undersea tunnel construction,the design and construction technologies have been greatly enhanced.The first undersea tunnel in China has just been built.Waterproofing is the key technique of undersea tunneling.A new concept of waterproofing scheme of grouting,sealing,draining and divided sections was adopted in the construction of the tunnel based on the researches,the in-situ geological features,the astuteness of the current technology,and the cost of construction.The structural details of the sealing and draining system are introduced to illustrate the salient features of the new waterproofing technique.It is hoped that experiences described in the paper can offer guidance for the construction of the extensive undersea tunnels in the coming years.     

多参数水质测试仪和碘量法测定海水溶解氧含量的比较与分析

通过对碘量法和多参数水质测试仪测定海水中溶解氧比对数据的系统误差检验,分析两种方法间系统偏离差异的显著程度。探讨多参数水质测试仪业务化应用的可行性,以在保证监测质量的前提下,切实提高监测工作效率。     

自适应Chirplet变换及其在探地雷达目标探测中的应用(英文)

探地雷达不仅能够探测金属目标体,而且能够探测非金属目标体,而成为UX0和地雷探测的一种重要的浅部地球物理方法。但是在地雷和UX0探测中,目标体埋藏深度浅,在探地雷达数据信噪比较低情况下,地表和土壤层的反射严重干扰对目标体的拾取。本文采用自适用Chirplet变换来消除地表层和土壤层变化的干扰,并在Radon—Wigner分布的基础上,采用自适用Chirplet变换来拾取目标体的信号。通过对实际探测实验数据应用证明,本方法处理结果比传统的偏移方法具有较高的信噪比,并能清晰地提取目标体信号。     

Three-layer model for vertical velocity distribution in open channel flow with submerged rigid vegetation

Based on the detailed laboratory experiments and theoretical analysis, a new three-layer model is proposed to predict the vertical velocity distribution in an open channel flow with submerged vegetation. The time averaged velocity and turbulence behaviour of a steady uniform flow with fully submerged artificial rigid vegetation was measured using a 3D Micro ADV, and the vertical distribution of velocity and Reynolds shear stress at different vegetation height, vegetation density and measuring positions were obtained. The results show that the velocity profile consists of three hydrodynamic regimes (i.e. the upper non-vegetated layer, the outer and bottom layer within vegetation); accordingly different methods had been adopted to describe the vertical velocity distribution. For the upper non-vegetated layer, a modified mixing length theory combined with the concept of ‘the new vegetation boundary layer’ was adopted, and an analytical model was presented to predict the vertical velocity distribution in this region. For the bottom layer within vegetation, the depth average velocity was obtained by numerically solving the momentum equations. For the upper layer within vegetation, the analytical solution was presented by expressing the shear stress as a formula fitted to the experimental data. Finally, the analytical predictions of the vertical velocity over the whole flow depth were compared with the results obtained by other researchers, and the good agreement proved that the three-layer model can be used to predict the velocity distribution of the open channel flow with submerged rigid vegetation.